An Organic Light-emitting Display (OLED) has become a new flat panel display device researched and developed in recent years by virtue of its merits of high brightness, wide viewing angle, active luminescence, high contrast, ultrathin, portability and so on.
The packaging technology of an OLED display panel is a key process to raise the lifetime of an OLED display device, and this is because the main reasons affecting the lifetime of the OLED display device are as follows: 1) a cathode of the OLED display panel usually adopts a metal with a lower work function, and so, when H2O and O2 are present, H2O and O2 may react with the metal, and this leads to protuberance of the cathode and degradation in the device performance; 2) O2 is a triplet quencher itself, and moreover an organic luminescent material is oxidized by O2 to generate a carbonyl compound (black spots), which may lead to significant reduction in luminescent quantum efficiency; 3) other organic functional material in an OLED luminescent layer may also be oxidized by O2, resulting in deterioration in the performance of the OLED display device. Therefore, it is necessary to research and develop an effective packaging technology for blocking (or preventing) H2O and O2.
At present, a packaging mode with good packaging effect is glass frit encapsulation, and a commonly used packaging structure is that a light extraction layer is directly provided on a surface of an OLED luminescent layer.